Gemini 3.5 vs GPT-5.5
2026 - Pricing, benchmarks, and use case comparison
Quick take
- •GPT-5.5 is open-weights - free to self-host with no API costs. Gemini 3.5 requires paid API access.
- •Gemini 3.5 has a 1M context window - 8x larger than GPT-5.5's 128K. Better for long documents and large codebases.
Specs comparison
| Gemini 3.5 | GPT-5.5 | |
|---|---|---|
| Provider | Google DeepMind | OpenAI |
| Type | Closed source | Closed source |
| Context window | ✓1M | 128K |
| Input / 1M tokens | TBA | ✓Free (self-host) |
| Output / 1M tokens | TBA | Free (self-host) |
| Release date | 2026-05 | 2026-04 |
Strengths
Gemini 3.5
- ✓Action-first architecture for agentic and multi-step workflows
- ✓1M token context window - largest in class
- ✓Powers Google Antigravity CLI for terminal-native coding
- ✓Native Workspace integration with autonomous task execution
- ✓Companion Gemini Omni handles anything-to-anything multimodal generation
GPT-5.5
- ✓Improved instruction following over GPT-4o
- ✓Stronger long-context coherence
- ✓Better output consistency for agentic pipelines
- ✓GPT-5.5 Pro tier for reliability-critical workloads
- ✓Easier migration path than jumping from GPT-4o to GPT-5
Which should you choose?
Choose Gemini 3.5 if you need...
- →Agentic workflows requiring multi-step tool use
- →Large codebase comprehension and editing
- →Google Workspace automation
- →Long document and multimodal analysis
Choose GPT-5.5 if you need...
- →Production API integrations migrating from GPT-4o
- →Agentic workflows needing consistent structured output
- →Long-context document tasks
- →Teams deferring full GPT-5 migration costs